Spy++ view messages posted/sent to a control, or from it?

i noticed that there are "S", "P" codes when the messages are logged. Now what i wan to know is these messages are messages originating from that control, OR they are messages being received by that control.

if they are messages sent away, how do i see messages being sent to that control?

if they are messages sent to, how do i see messages being sent away from that control

if they are both, then how do i differentiate then? how to know which is which

how do i know the destination of the messages being sent?

please help a newb
hanhao